<?php
/**
 * PHPExcel
 *
 * Copyright (c) 2006 - 2011 PHPExcel
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * @category    PHPExcel
 * @package        PHPExcel_Calculation
 * @copyright    Copyright (c) 2006 - 2011 PHPExcel (http://www.codeplex.com/PHPExcel)
 * @license        http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
 * @version        1.7.6, 2011-02-27
 */


/** PHPExcel root directory */
if (!defined('PHPEXCEL_ROOT')) {
    /**
     * @ignore
     */
    define('PHPEXCEL_ROOT', dirname(__FILE__) . '/../../');
    require(PHPEXCEL_ROOT . 'PHPExcel/Autoloader.php');
}


/**
 * PHPExcel_Calculation_LookupRef
 *
 * @category    PHPExcel
 * @package        PHPExcel_Calculation
 * @copyright    Copyright (c) 2006 - 2011 PHPExcel (http://www.codeplex.com/PHPExcel)
 */
class PHPExcel_Calculation_LookupRef {


    /**
     *    CELL_ADDRESS
     *
     *    Creates a cell address as text, given specified row and column numbers.
     *
     *    @param    row                Row number to use in the cell reference
     *    @param    column            Column number to use in the cell reference
     *    @param    relativity        Flag indicating the type of reference to return
     *                                1 or omitted    Absolute
     *                                2                Absolute row; relative column
     *                                3                Relative row; absolute column
     *                                4                Relative
     *    @param    referenceStyle    A logical value that specifies the A1 or R1C1 reference style.
     *                                TRUE or omitted        CELL_ADDRESS returns an A1-style reference
     *                                FALSE                CELL_ADDRESS returns an R1C1-style reference
     *    @param    sheetText        Optional Name of worksheet to use
     *    @return    string
     */
    public static function CELL_ADDRESS($row, $column, $relativity=1, $referenceStyle=True, $sheetText='') {
        $row        = PHPExcel_Calculation_Functions::flattenSingleValue($row);
        $column        = PHPExcel_Calculation_Functions::flattenSingleValue($column);
        $relativity    = PHPExcel_Calculation_Functions::flattenSingleValue($relativity);
        $sheetText    = PHPExcel_Calculation_Functions::flattenSingleValue($sheetText);

        if (($row < 1) || ($column < 1)) {
            return PHPExcel_Calculation_Functions::VALUE();
        }

        if ($sheetText > '') {
            if (strpos($sheetText,' ') !== False) { $sheetText = "'".$sheetText."'"; }
            $sheetText .='!';
        }
        if ((!is_bool($referenceStyle)) || $referenceStyle) {
            $rowRelative = $columnRelative = '$';
            $column = PHPExcel_Cell::stringFromColumnIndex($column-1);
            if (($relativity == 2) || ($relativity == 4)) { $columnRelative = ''; }
            if (($relativity == 3) || ($relativity == 4)) { $rowRelative = ''; }
            return $sheetText.$columnRelative.$column.$rowRelative.$row;
        } else {
            if (($relativity == 2) || ($relativity == 4)) { $column = '['.$column.']'; }
            if (($relativity == 3) || ($relativity == 4)) { $row = '['.$row.']'; }
            return $sheetText.'R'.$row.'C'.$column;
        }
    }    //    function CELL_ADDRESS()


    /**
     *    COLUMN
     *
     *    Returns the column number of the given cell reference
     *    If the cell reference is a range of cells, COLUMN returns the column numbers of each column in the reference as a horizontal array.
     *    If cell reference is omitted, and the function is being called through the calculation engine, then it is assumed to be the
     *        reference of the cell in which the COLUMN function appears; otherwise this function returns 0.
     *
     *    @param    cellAddress        A reference to a range of cells for which you want the column numbers
     *    @return    integer or array of integer
     */
    public static function COLUMN($cellAddress=Null) {
        if (is_null($cellAddress) || trim($cellAddress) === '') { return 0; }

        if (is_array($cellAddress)) {
            foreach($cellAddress as $columnKey => $value) {
                $columnKey = preg_replace('/[^a-z]/i','',$columnKey);
                return (integer) PHPExcel_Cell::columnIndexFromString($columnKey);
            }
        } else {
            if (strpos($cellAddress,'!') !== false) {
                list($sheet,$cellAddress) = explode('!',$cellAddress);
            }
            if (strpos($cellAddress,':') !== false) {
                list($startAddress,$endAddress) = explode(':',$cellAddress);
                $startAddress = preg_replace('/[^a-z]/i','',$startAddress);
                $endAddress = preg_replace('/[^a-z]/i','',$endAddress);
                $returnValue = array();
                do {
                    $returnValue[] = (integer) PHPExcel_Cell::columnIndexFromString($startAddress);
                } while ($startAddress++ != $endAddress);
                return $returnValue;
            } else {
                $cellAddress = preg_replace('/[^a-z]/i','',$cellAddress);
                return (integer) PHPExcel_Cell::columnIndexFromString($cellAddress);
            }
        }
    }    //    function COLUMN()


    /**
     *    COLUMNS
     *
     *    Returns the number of columns in an array or reference.
     *
     *    @param    cellAddress        An array or array formula, or a reference to a range of cells for which you want the number of columns
     *    @return    integer
     */
    public static function COLUMNS($cellAddress=Null) {
        if (is_null($cellAddress) || $cellAddress === '') {
            return 1;
        } elseif (!is_array($cellAddress)) {
            return PHPExcel_Calculation_Functions::VALUE();
        }

        $x = array_keys($cellAddress);
        $x = array_shift($x);
        $isMatrix = (is_numeric($x));
        list($columns,$rows) = PHPExcel_Calculation::_getMatrixDimensions($cellAddress);

        if ($isMatrix) {
            return $rows;
        } else {
            return $columns;
        }
    }    //    function COLUMNS()


    /**
     *    ROW
     *
     *    Returns the row number of the given cell reference
     *    If the cell reference is a range of cells, ROW returns the row numbers of each row in the reference as a vertical array.
     *    If cell reference is omitted, and the function is being called through the calculation engine, then it is assumed to be the
     *        reference of the cell in which the ROW function appears; otherwise this function returns 0.
     *
     *    @param    cellAddress        A reference to a range of cells for which you want the row numbers
     *    @return    integer or array of integer
     */
    public static function ROW($cellAddress=Null) {
        if (is_null($cellAddress) || trim($cellAddress) === '') { return 0; }

        if (is_array($cellAddress)) {
            foreach($cellAddress as $columnKey => $rowValue) {
                foreach($rowValue as $rowKey => $cellValue) {
                    return (integer) preg_replace('/[^0-9]/i','',$rowKey);
                }
            }
        } else {
            if (strpos($cellAddress,'!') !== false) {
                list($sheet,$cellAddress) = explode('!',$cellAddress);
            }
            if (strpos($cellAddress,':') !== false) {
                list($startAddress,$endAddress) = explode(':',$cellAddress);
                $startAddress = preg_replace('/[^0-9]/','',$startAddress);
                $endAddress = preg_replace('/[^0-9]/','',$endAddress);
                $returnValue = array();
                do {
                    $returnValue[][] = (integer) $startAddress;
                } while ($startAddress++ != $endAddress);
                return $returnValue;
            } else {
                list($cellAddress) = explode(':',$cellAddress);
                return (integer) preg_replace('/[^0-9]/','',$cellAddress);
            }
        }
    }    //    function ROW()


    /**
     *    ROWS
     *
     *    Returns the number of rows in an array or reference.
     *
     *    @param    cellAddress        An array or array formula, or a reference to a range of cells for which you want the number of rows
     *    @return    integer
     */
    public static function ROWS($cellAddress=Null) {
        if (is_null($cellAddress) || $cellAddress === '') {
            return 1;
        } elseif (!is_array($cellAddress)) {
            return PHPExcel_Calculation_Functions::VALUE();
        }

        $i = array_keys($cellAddress);
        $isMatrix = (is_numeric(array_shift($i)));
        list($columns,$rows) = PHPExcel_Calculation::_getMatrixDimensions($cellAddress);

        if ($isMatrix) {
            return $columns;
        } else {
            return $rows;
        }
    }    //    function ROWS()


    /**
     *    HYPERLINK
     *
     *    Excel Function:
     *        =HYPERLINK(linkURL,displayName)
     *
     *    @access    public
     *    @category Logical Functions
     *    @param    string    $linkURL        Value to check, is also the value returned when no error
     *    @param    string    $displayName    Value to return when testValue is an error condition
     *    @return    mixed    The value of errorpart or testValue determined by error condition
     */
    public static function HYPERLINK($linkURL = '', $displayName = null, PHPExcel_Cell $pCell = null) {
        $args = func_get_args();
        $pCell = array_pop($args);

        $linkURL        = (is_null($linkURL))        ? '' :    PHPExcel_Calculation_Functions::flattenSingleValue($linkURL);
        $displayName    = (is_null($displayName))    ? '' :    PHPExcel_Calculation_Functions::flattenSingleValue($displayName);

        if ((!is_object($pCell)) || (trim($linkURL) == '')) {
            return PHPExcel_Calculation_Functions::REF();
        }

        if ((is_object($displayName)) || trim($displayName) == '') {
            $displayName = $linkURL;
        }

        $pCell->getHyperlink()->setUrl($linkURL);

        return $displayName;
    }    //    function HYPERLINK()


    /**
     *    INDIRECT
     *
     *    Returns the number of rows in an array or reference.
     *
     *    @param    cellAddress        An array or array formula, or a reference to a range of cells for which you want the number of rows
     *    @return    integer
     */
    public static function INDIRECT($cellAddress=Null, PHPExcel_Cell $pCell = null) {
        $cellAddress    = PHPExcel_Calculation_Functions::flattenSingleValue($cellAddress);
        if (is_null($cellAddress) || $cellAddress === '') {
            return PHPExcel_Calculation_Functions::REF();
        }

        $cellAddress1 = $cellAddress;
        $cellAddress2 = NULL;
        if (strpos($cellAddress,':') !== false) {
            list($cellAddress1,$cellAddress2) = explode(':',$cellAddress);
        }

        if ((!preg_match('/^'.PHPExcel_Calculation::CALCULATION_REGEXP_CELLREF.'$/i', $cellAddress1, $matches)) ||
            ((!is_null($cellAddress2)) && (!preg_match('/^'.PHPExcel_Calculation::CALCULATION_REGEXP_CELLREF.'$/i', $cellAddress2, $matches)))) {
            return PHPExcel_Calculation_Functions::REF();
        }

        if (strpos($cellAddress,'!') !== false) {
            list($sheetName,$cellAddress) = explode('!',$cellAddress);
            $pSheet = $pCell->getParent()->getParent()->getSheetByName($sheetName);
        } else {
            $pSheet = $pCell->getParent();
        }

        return PHPExcel_Calculation::getInstance()->extractCellRange($cellAddress, $pSheet, False);
    }    //    function INDIRECT()


    /**
     *    OFFSET
     *
     *    Returns a reference to a range that is a specified number of rows and columns from a cell or range of cells.
     *    The reference that is returned can be a single cell or a range of cells. You can specify the number of rows and
     *    the number of columns to be returned.
     *
     *    @param    cellAddress        The reference from which you want to base the offset. Reference must refer to a cell or
     *                                range of adjacent cells; otherwise, OFFSET returns the #VALUE! error value.
     *    @param    rows            The number of rows, up or down, that you want the upper-left cell to refer to.
     *                                Using 5 as the rows argument specifies that the upper-left cell in the reference is
     *                                five rows below reference. Rows can be positive (which means below the starting reference)
     *                                or negative (which means above the starting reference).
     *    @param    cols            The number of columns, to the left or right, that you want the upper-left cell of the result
     *                                to refer to. Using 5 as the cols argument specifies that the upper-left cell in the
     *                                reference is five columns to the right of reference. Cols can be positive (which means
     *                                to the right of the starting reference) or negative (which means to the left of the
     *                                starting reference).
     *    @param    height            The height, in number of rows, that you want the returned reference to be. Height must be a positive number.
     *    @param    width            The width, in number of columns, that you want the returned reference to be. Width must be a positive number.
     *    @return    string            A reference to a cell or range of cells
     */
    public static function OFFSET($cellAddress=Null,$rows=0,$columns=0,$height=null,$width=null) {
        $rows        = PHPExcel_Calculation_Functions::flattenSingleValue($rows);
        $columns    = PHPExcel_Calculation_Functions::flattenSingleValue($columns);
        $height        = PHPExcel_Calculation_Functions::flattenSingleValue($height);
        $width        = PHPExcel_Calculation_Functions::flattenSingleValue($width);
        if ($cellAddress == Null) {
            return 0;
        }

        $args = func_get_args();
        $pCell = array_pop($args);
        if (!is_object($pCell)) {
            return PHPExcel_Calculation_Functions::REF();
        }

        $sheetName = null;
        if (strpos($cellAddress,"!")) {
            list($sheetName,$cellAddress) = explode("!",$cellAddress);
        }
        if (strpos($cellAddress,":")) {
            list($startCell,$endCell) = explode(":",$cellAddress);
        } else {
            $startCell = $endCell = $cellAddress;
        }
        list($startCellColumn,$startCellRow) = PHPExcel_Cell::coordinateFromString($startCell);
        list($endCellColumn,$endCellRow) = PHPExcel_Cell::coordinateFromString($endCell);

        $startCellRow += $rows;
        $startCellColumn = PHPExcel_Cell::columnIndexFromString($startCellColumn) - 1;
        $startCellColumn += $columns;

        if (($startCellRow <= 0) || ($startCellColumn < 0)) {
            return PHPExcel_Calculation_Functions::REF();
        }
        $endCellColumn = PHPExcel_Cell::columnIndexFromString($endCellColumn) - 1;
        if (($width != null) && (!is_object($width))) {
            $endCellColumn = $startCellColumn + $width - 1;
        } else {
            $endCellColumn += $columns;
        }
        $startCellColumn = PHPExcel_Cell::stringFromColumnIndex($startCellColumn);

        if (($height != null) && (!is_object($height))) {
            $endCellRow = $startCellRow + $height - 1;
        } else {
            $endCellRow += $rows;
        }

        if (($endCellRow <= 0) || ($endCellColumn < 0)) {
            return PHPExcel_Calculation_Functions::REF();
        }
        $endCellColumn = PHPExcel_Cell::stringFromColumnIndex($endCellColumn);

        $cellAddress = $startCellColumn.$startCellRow;
        if (($startCellColumn != $endCellColumn) || ($startCellRow != $endCellRow)) {
            $cellAddress .= ':'.$endCellColumn.$endCellRow;
        }

        if ($sheetName !== null) {
            $pSheet = $pCell->getParent()->getParent()->getSheetByName($sheetName);
        } else {
            $pSheet = $pCell->getParent();
        }

        return PHPExcel_Calculation::getInstance()->extractCellRange($cellAddress, $pSheet, False);
    }    //    function OFFSET()


    public static function CHOOSE() {
        $chooseArgs = func_get_args();
        $chosenEntry = PHPExcel_Calculation_Functions::flattenArray(array_shift($chooseArgs));
        $entryCount = count($chooseArgs) - 1;

        if(is_array($chosenEntry)) {
            $chosenEntry = array_shift($chosenEntry);
        }
        if ((is_numeric($chosenEntry)) && (!is_bool($chosenEntry))) {
            --$chosenEntry;
        } else {
            return PHPExcel_Calculation_Functions::VALUE();
        }
        $chosenEntry = floor($chosenEntry);
        if (($chosenEntry <= 0) || ($chosenEntry > $entryCount)) {
            return PHPExcel_Calculation_Functions::VALUE();
        }

        if (is_array($chooseArgs[$chosenEntry])) {
            return PHPExcel_Calculation_Functions::flattenArray($chooseArgs[$chosenEntry]);
        } else {
            return $chooseArgs[$chosenEntry];
        }
    }    //    function CHOOSE()


    /**
     *    MATCH
     *
     *    The MATCH function searches for a specified item in a range of cells
     *
     *    @param    lookup_value    The value that you want to match in lookup_array
     *    @param    lookup_array    The range of cells being searched
     *    @param    match_type        The number -1, 0, or 1. -1 means above, 0 means exact match, 1 means below. If match_type is 1 or -1, the list has to be ordered.
     *    @return    integer            The relative position of the found item
     */
    public static function MATCH($lookup_value, $lookup_array, $match_type=1) {
        $lookup_array = PHPExcel_Calculation_Functions::flattenArray($lookup_array);
        $lookup_value = PHPExcel_Calculation_Functions::flattenSingleValue($lookup_value);
        $match_type    = (is_null($match_type)) ? 1 : (int) PHPExcel_Calculation_Functions::flattenSingleValue($match_type);
        //    MATCH is not case sensitive
        $lookup_value = strtolower($lookup_value);

        //    lookup_value type has to be number, text, or logical values
        if ((!is_numeric($lookup_value)) && (!is_string($lookup_value)) && (!is_bool($lookup_value))) {
            return PHPExcel_Calculation_Functions::NA();
        }

        //    match_type is 0, 1 or -1
        if (($match_type !== 0) && ($match_type !== -1) && ($match_type !== 1)) {
            return PHPExcel_Calculation_Functions::NA();
        }

        //    lookup_array should not be empty
        $lookupArraySize = count($lookup_array);
        if ($lookupArraySize <= 0) {
            return PHPExcel_Calculation_Functions::NA();
        }

        //    lookup_array should contain only number, text, or logical values, or empty (null) cells
        foreach($lookup_array as $i => $lookupArrayValue) {
            //    check the type of the value
            if ((!is_numeric($lookupArrayValue)) && (!is_string($lookupArrayValue)) &&
                (!is_bool($lookupArrayValue)) && (!is_null($lookupArrayValue))) {
                return PHPExcel_Calculation_Functions::NA();
            }
            //    convert strings to lowercase for case-insensitive testing
            if (is_string($lookupArrayValue)) {
                $lookup_array[$i] = strtolower($lookupArrayValue);
            }
            if ((is_null($lookupArrayValue)) && (($match_type == 1) || ($match_type == -1))) {
                $lookup_array = array_slice($lookup_array,0,$i-1);
            }
        }

        // if match_type is 1 or -1, the list has to be ordered
        if ($match_type == 1) {
            asort($lookup_array);
            $keySet = array_keys($lookup_array);
        } elseif($match_type == -1) {
            arsort($lookup_array);
            $keySet = array_keys($lookup_array);
        }

        // **
        // find the match
        // **
        // loop on the cells
//        var_dump($lookup_array);
//        echo '<br />';
        foreach($lookup_array as $i => $lookupArrayValue) {
            if (($match_type == 0) && ($lookupArrayValue == $lookup_value)) {
                //    exact match
                return ++$i;
            } elseif (($match_type == -1) && ($lookupArrayValue <= $lookup_value)) {
//                echo '$i = '.$i.' => ';
//                var_dump($lookupArrayValue);
//                echo '<br />';
//                echo 'Keyset = ';
//                var_dump($keySet);
//                echo '<br />';
                $i = array_search($i,$keySet);
//                echo '$i='.$i.'<br />';
                // if match_type is -1 <=> find the smallest value that is greater than or equal to lookup_value
                if ($i < 1){
                    // 1st cell was allready smaller than the lookup_value
                    break;
                } else {
                    // the previous cell was the match
                    return $keySet[$i-1]+1;
                }
            } elseif (($match_type == 1) && ($lookupArrayValue >= $lookup_value)) {
//                echo '$i = '.$i.' => ';
//                var_dump($lookupArrayValue);
//                echo '<br />';
//                echo 'Keyset = ';
//                var_dump($keySet);
//                echo '<br />';
                $i = array_search($i,$keySet);
//                echo '$i='.$i.'<br />';
                // if match_type is 1 <=> find the largest value that is less than or equal to lookup_value
                if ($i < 1){
                    // 1st cell was allready bigger than the lookup_value
                    break;
                } else {
                    // the previous cell was the match
                    return $keySet[$i-1]+1;
                }
            }
        }

        //    unsuccessful in finding a match, return #N/A error value
        return PHPExcel_Calculation_Functions::NA();
    }    //    function MATCH()


    /**
     *    INDEX
     *
     * Uses an index to choose a value from a reference or array
     * implemented: Return the value of a specified cell or array of cells    Array form
     * not implemented: Return a reference to specified cells    Reference form
     *
     * @param    range_array    a range of cells or an array constant
     * @param    row_num        selects the row in array from which to return a value. If row_num is omitted, column_num is required.
     * @param    column_num    selects the column in array from which to return a value. If column_num is omitted, row_num is required.
     */
    public static function INDEX($arrayValues,$rowNum = 0,$columnNum = 0) {

        if (($rowNum < 0) || ($columnNum < 0)) {
            return PHPExcel_Calculation_Functions::VALUE();
        }

        if (!is_array($arrayValues)) {
            return PHPExcel_Calculation_Functions::REF();
        }

        $rowKeys = array_keys($arrayValues);
        $columnKeys = @array_keys($arrayValues[$rowKeys[0]]);

        if ($columnNum > count($columnKeys)) {
            return PHPExcel_Calculation_Functions::VALUE();
        } elseif ($columnNum == 0) {
            if ($rowNum == 0) {
                return $arrayValues;
            }
            $rowNum = $rowKeys[--$rowNum];
            $returnArray = array();
            foreach($arrayValues as $arrayColumn) {
                if (is_array($arrayColumn)) {
                    if (isset($arrayColumn[$rowNum])) {
                        $returnArray[] = $arrayColumn[$rowNum];
                    } else {
                        return $arrayValues[$rowNum];
                    }
                } else {
                    return $arrayValues[$rowNum];
                }
            }
            return $returnArray;
        }
        $columnNum = $columnKeys[--$columnNum];
        if ($rowNum > count($rowKeys)) {
            return PHPExcel_Calculation_Functions::VALUE();
        } elseif ($rowNum == 0) {
            return $arrayValues[$columnNum];
        }
        $rowNum = $rowKeys[--$rowNum];

        return $arrayValues[$rowNum][$columnNum];
    }    //    function INDEX()


    /**
     * TRANSPOSE
     *
     * @param    array    $matrixData    A matrix of values
     * @return    array
     *
     * Unlike the Excel TRANSPOSE function, which will only work on a single row or column, this function will transpose a full matrix.
     */
    public static function TRANSPOSE($matrixData) {
        $returnMatrix = array();
        if (!is_array($matrixData)) { $matrixData = array(array($matrixData)); }

        $column = 0;
        foreach($matrixData as $matrixRow) {
            $row = 0;
            foreach($matrixRow as $matrixCell) {
                $returnMatrix[$row][$column] = $matrixCell;
                ++$row;
            }
            ++$column;
        }
        return $returnMatrix;
    }    //    function TRANSPOSE()


    private static function _vlookupSort($a,$b) {
        $f = array_keys($a);
        $firstColumn = array_shift($f);
        if (strtolower($a[$firstColumn]) == strtolower($b[$firstColumn])) {
            return 0;
        }
        return (strtolower($a[$firstColumn]) < strtolower($b[$firstColumn])) ? -1 : 1;
    }    //    function _vlookupSort()


    /**
    * VLOOKUP
    * The VLOOKUP function searches for value in the left-most column of lookup_array and returns the value in the same row based on the index_number.
    * @param    lookup_value    The value that you want to match in lookup_array
    * @param    lookup_array    The range of cells being searched
    * @param    index_number    The column number in table_array from which the matching value must be returned. The first column is 1.
    * @param    not_exact_match    Determines if you are looking for an exact match based on lookup_value.
    * @return    mixed            The value of the found cell
    */
    public static function VLOOKUP($lookup_value, $lookup_array, $index_number, $not_exact_match=true) {
        $lookup_value    = PHPExcel_Calculation_Functions::flattenSingleValue($lookup_value);
        $index_number    = PHPExcel_Calculation_Functions::flattenSingleValue($index_number);
        $not_exact_match    = PHPExcel_Calculation_Functions::flattenSingleValue($not_exact_match);

        // index_number must be greater than or equal to 1
        if ($index_number < 1) {
            return PHPExcel_Calculation_Functions::VALUE();
        }

        // index_number must be less than or equal to the number of columns in lookup_array
        if ((!is_array($lookup_array)) || (count($lookup_array) < 1)) {
            return PHPExcel_Calculation_Functions::REF();
        } else {
            $f = array_keys($lookup_array);
            $firstRow = array_pop($f);
            if ((!is_array($lookup_array[$firstRow])) || ($index_number > count($lookup_array[$firstRow]))) {
                return PHPExcel_Calculation_Functions::REF();
            } else {
                $columnKeys = array_keys($lookup_array[$firstRow]);
                $returnColumn = $columnKeys[--$index_number];
                $firstColumn = array_shift($columnKeys);
            }
        }

        if (!$not_exact_match) {
            uasort($lookup_array,array('self','_vlookupSort'));
        }

        $rowNumber = $rowValue = False;
        foreach($lookup_array as $rowKey => $rowData) {
            if (strtolower($rowData[$firstColumn]) > strtolower($lookup_value)) {
                break;
            }
            $rowNumber = $rowKey;
            $rowValue = $rowData[$firstColumn];
        }

        if ($rowNumber !== false) {
            if ((!$not_exact_match) && ($rowValue != $lookup_value)) {
                //    if an exact match is required, we have what we need to return an appropriate response
                return PHPExcel_Calculation_Functions::NA();
            } else {
                //    otherwise return the appropriate value
                return $lookup_array[$rowNumber][$returnColumn];
            }
        }

        return PHPExcel_Calculation_Functions::NA();
    }    //    function VLOOKUP()


    /**
     * LOOKUP
     * The LOOKUP function searches for value either from a one-row or one-column range or from an array.
     * @param    lookup_value    The value that you want to match in lookup_array
     * @param    lookup_vector    The range of cells being searched
     * @param    result_vector    The column from which the matching value must be returned
     * @return    mixed            The value of the found cell
     */
    public static function LOOKUP($lookup_value, $lookup_vector, $result_vector=null) {
        $lookup_value    = PHPExcel_Calculation_Functions::flattenSingleValue($lookup_value);

        if (!is_array($lookup_vector)) {
            return PHPExcel_Calculation_Functions::NA();
        }
        $lookupRows = count($lookup_vector);
        $l = array_keys($lookup_vector);
        $l = array_shift($l);
        $lookupColumns = count($lookup_vector[$l]);
        if ((($lookupRows == 1) && ($lookupColumns > 1)) || (($lookupRows == 2) && ($lookupColumns != 2))) {
            $lookup_vector = self::TRANSPOSE($lookup_vector);
            $lookupRows = count($lookup_vector);
            $l = array_keys($lookup_vector);
            $lookupColumns = count($lookup_vector[array_shift($l)]);
        }

        if (is_null($result_vector)) {
            $result_vector = $lookup_vector;
        }
        $resultRows = count($result_vector);
        $l = array_keys($result_vector);
        $l = array_shift($l);
        $resultColumns = count($result_vector[$l]);
        if ((($resultRows == 1) && ($resultColumns > 1)) || (($resultRows == 2) && ($resultColumns != 2))) {
            $result_vector = self::TRANSPOSE($result_vector);
            $resultRows = count($result_vector);
            $r = array_keys($result_vector);
            $resultColumns = count($result_vector[array_shift($r)]);
        }

        if ($lookupRows == 2) {
            $result_vector = array_pop($lookup_vector);
            $lookup_vector = array_shift($lookup_vector);
        }
        if ($lookupColumns != 2) {
            foreach($lookup_vector as &$value) {
                if (is_array($value)) {
                    $k = array_keys($value);
                    $key1 = $key2 = array_shift($k);
                    $key2++;
                    $dataValue1 = $value[$key1];
                } else {
                    $key1 = 0;
                    $key2 = 1;
                    $dataValue1 = $value;
                }
                $dataValue2 = array_shift($result_vector);
                if (is_array($dataValue2)) {
                    $dataValue2 = array_shift($dataValue2);
                }
                $value = array($key1 => $dataValue1, $key2 => $dataValue2);
            }
            unset($value);
        }

        return self::VLOOKUP($lookup_value,$lookup_vector,2);
     }    //    function LOOKUP()

}    //    class PHPExcel_Calculation_LookupRef
